E CEcology and consErvationof EuropEan forEst-dwElling

raptorsiñigo ZubErogoitia & José EnriquE MartínEZ (Eds.)

Estudios Medioambientales Icarus S.L.

Marc Galvez.

Published by:Departamento de Agricultura de la Diputación Foral de Bizkaia

© Diputación Foral de BizkaiaAll rights reserved. No part of this publication may be reproduced in any form or by any means without the prior permission of the copyright owner.

Edited by:Iñigo Zuberogoitia & José Enrique MartínezEstudios Medioambientales Icarus S.L.

Project Supervision:Antonio Galera Coleto, Director of the Department of Conservation, Natura 2000 Network and Biodiversity.

Graphic and maps Design:Antonio Secilla

General Design:ITZEL Digital, S.L.

Printer:Berekintza, S.L.

Cover photo by:Sparrowhawk. Juán Sagardía.

Translators:Phillip ThomasJosé DelgadoMaria Francia Iñiguez PueblaMikel John O´RourkeRally Haigh

I.S.B.N.: 978-84-7752-489-2D.L.: 1730-2011

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pairs of hobbies (Falco subbuteo) or around 1000 pairs of common buzzard.

Study of the population of forest raptors in Biscay

It would be practically impossible to carry out a detailed study of raptors in the whole of Biscay since it covers a total area of 2,212 km2, of which 71.9% is covered by forest. In 1996 we began to monitor the common buzzard population in 40 km2 of the Txori-Herri valley, in the central-north of Biscay (see Zuberogoitia et al., 2005, 2006). In 1997 we decided to focus our efforts on seven areas, covering a total of 708 km2 (32% of the area of Biscay, see Fig. 6). Within these areas, we selected eight areas for intensive monitoring totalling 75 km2. Finally, in 1999 the study area was widened and all the other raptors existing in Biscay were included.

The selection of individual monitoring zones obeyed landscape criteria in an attempt to cover a wide spec-trum of forest formations that could be considered typical of Biscay. In recent years, we have widened the zones in the search for nests and used data from other

Antecedents. Knowledge of forest raptors

The first references to the state of forest raptors in Bis-cay date from the late 1970’s and are very generalist in nature. Álvarez et al. (1985) and Galarza (1989) considered as scarce, rare or even absent most species of forest raptor, except the common buzzard (Buteo buteo), which they considered common and widely distributed, and the sparrowhawk (Accipiter nisus), which they described as widespread with unknown status. Subsequent to these studies, no more publica-tions on the forest raptors of Biscay were published until the end of the XX century. In the absence of other data, the studies which analysed the status of conservation and population trends of these birds, both at regional level (see Martí & Del Moral, 2003; Madroño et al., 2005) were based on these previous publications. Hence, in the Catalogue of Threatened Species in the Basque Country (Fernández & Bea, 1998) the popula-tion of most species is described as unknown, although estimates were made for some species: for example, 70-100 pairs of honey buzzard (Pernis apivorus), 26

Population trends of diurnal forest raptors in Biscay

Iñigo Zuberogoitia1, Iñaki Castillo, Jabi Zabala, Agurtzane Iraeta & Ainara Azkona1 Estudios Medioambientales Icarus S.L. Pintor Sorolla 6 1º C 26007 Logroño. La Rioja. Spain

E-mail: zuberogoitia@icarus.es

Figure 6. Areas of high sampling effort (shaded in grey) and areas of intensive monitoring (bordered in red) of forest raptors in Biscay.

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Forest raptor composition changes as the forest area in-creases and its fragmentation diminishes. In the valleys resulting from the flow of the river Butrón (30T WN19), in which meadows abound and eucalyptus is more common than in the case of the Txori Herri, the density of common buzzard and sparrowhawk falls by a half, that of hobby falls slightly, while the density of honey buzzard is maintained and that of black kite doubles.

When the landscape is more or less totally composed of pine woods alternating with mixed oakwoods bordered by grassfields, and urban areas become less frequent as the relief increases (30T VN88), common buzzard den-sities fall by half, hobbies and honey buzzards remain constant and sparrowhawks increase to reach their maximum of 9 territories/100 km2. This is accompanied by a considerable increase in black kite due to a nesting colony, and territories of goshawks and booted eagle (Aquila pennata) appear.

In areas where eucalyptus plantation run along moun-tain slopes, interspersed with pines and some mixed woods, with meadows along the valley floor (30T VN89), the maximum density of honey buzzard is ac-companied by an unchanged density of common buz-zard and decreased densities of sparrowhawks, hobbies and black kites.

field studies (e.g. Zuberogoitia et al., 2008, 2009) to provide an overall picture of raptor nesting in “low density sampling” zones.

Population sizes and densities

Nine species of diurnal forest raptor nest in Biscay, the common buzzard, black kite (Milvus migrans) and sparrowhawk being the most abundant and widely distributed (Table 5).

The cover is not the same for all the species, since the common buzzard shows a regular distribution pattern, while the honey buzzard, black kite and hobby show a tendency to congregate in favourable zones and sparrow-hawks show a somewhat random distribution (Table 6).

Inspection of the distribution of nesting territories (Fig. 7) points to a certain separation of the species. For example, in the Txori Herri valley (30T WN09), where the landscape is strongly fragmented and where small forest plantations are interspersed with open spaces (e.g. Bilbao airport) and urban and industrial areas, we find the highest densities of common buzzards (25 terri-tories/100 km2, Table 7), accompanied by high densities of hobbies, medium high densities of honey buzzards and low densities of black kites.

Species

Territories with nests closely

monitored and inspected

Territories with nests not closely monitored

but with signs of successful breeding

Total number of territories identified

Common buzzard 66 154 220honey buzzard 20 19 39Goshawk 10 5 15Booted eagle 4 6 9Short-toed eagle 0 4 4Black kite 25 45 70Red kite 0 1 1Sparrowhawk 45 28 73hobby 35 10 45

Table 5. Number of territories located for each species of diurnal forest raptor. We depict the number of territories in which nests were monitored, closely registered and the chicks ringed. We also depict the territories in which nests were located but not closely monitored or inspected, but in which fledglings were de-tected or which showed signs of having been used to raise chicks.

Species Distribution pattern Z value

Nearest neighbour distance (m)

Min. Mean

Common buzzard Regular 3.195 413 3072honey buzzard Grouped -2.091 843 6870Goshawk Randomly dispersed 1.077 2147 11328Black kite Grouped -5.792 233 3883Sparrowhawk Randomly dispersed 0.0193 555 5217hobby Grouped -2.218 298 6792

Table 6. Distribution of nests of different species of diurnal forest raptor based on nearest neighbour distance and distance analysis program of “Move-ment” from Arcview 3.0 (see Zabala et al., 2006). Species with few or very occasionally seen nests are not included.

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Figure 7. Location of nesting territories of forest raptors in Biscay.

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reaches considerable densities (see Table 7 and Fig. 7), while we have observed its presence in territories that are included in the Biosphere Reserve of Urdaibai. The same may be said of hobbies, which were considered infrequent in the 1980s and irregularly distributed, only being found in 14% of the squares covering Biscay (Ál-varez et al., 1985), Galarza (1989) did not mentioned it in the Biosphere Reserve of Urdaibai and García Tejedor (1998) cited a population of 26 pairs for the whole of the Basque Country. However, in 2000 we registered 41 nesting territories in Biscay (Iraeta et al., 2004). All these territories, except two that disappeared as a result of the felling of a whole forest and another that disappeared as a result of the pressure exercised by a pair of goshawks, remain and new territories have been founded, so that by 2009 we had identified 45 nesting territories (see Table 5 and Fig. 7).

The reason hobbies are so difficult to detect in Biscay is their choice of nesting site since they choose ma-ture forest plantations of Pinus radiata or Eucaliptus globulus, always in carrion crow (Corvus corone) nests, situated in the crowns of trees (see Zuberogoitia et al., 2003a; Iraeta et al., 2004). In other regions hobby nests are easier to detect since they nest in isolated trees or stands of trees in the middle of open spaces (Palacín, 2005), poplar trees or high tension poles (see Fiuczyn-ski & Nethersole-Thompson, 1980; Sergio & Bogliani,

Population trends

Analysis of data referring to local censuses and studies from the 1980s and 1990s (see Álvarez et al., 1985; Galarza, 1989; Fernández & Bea, 1998) and using data obtained on forest raptors in Biscay in the last 17 years, it is possible to obtain an approximate picture of the trends of the different species (Table 8).

A negative trend cannot be described for any of the species mentioned here, except for the short-toed eagle (Circaetus gallicus). Four groups can be identified: 1) abundant, difficult to detect species; 2) abundant, easy to detect species; 3) scarce, difficult to detect species and 4) scarce, easy to detect species showing a clearly positive trend.

Abundant, difficult to detect species

In studies dating from the 1980’s sparrowhawk was considered a widely distributed species. Álvarez et al. (1985) cited it in only 20% of 10 x 10 km squares in Biscay (Tabla 8). Galarza (1989) considered it a rare nesting bird in the Atlantic region of Biscay and absent from the Biosphere Reserve of Urdaibai. Based on these data, it must be considered that sparrowhawk has in-creased its population considerable in the last two dec-ades since it is common in the Atlantic region, where it

Species 30T wN09 30T wN19 30T vN88 30T vN89

Common buzzard 25 13 10 11honey buzzard 4 4 3 6Goshawk 0 0 1 2Booted eagle 0 2 1 1Short-toed eagle 0 0 0 0Black kite 2 4 9 4Red kite 0 0 0 0Sparrowhawk 8 4 9 5hobby 8 6 5 3

Table 7. Examples of variations in population density (territories/100 km2) of the nine species of breeding forest raptors in four UTM 10 x 10 km squares in Biscay. Note that these are territories with confirmed nesting sites. Note, too, that a third of square 30T VN89 is outside Biscay and its populations have not been considered.

Species 1 2 3 Trends

Common buzzard 6/17 + 220 +++honey buzzard 0/1 + 39 ++Goshawk 0/¿? 12 15 +Booted eagle 0/0 4 9 +Short-toed eagle 1/1 7 4 -Black kite 0/1 + 70 +++Red kite 0/0 2 1 (+)Sparrowhawk 3/7 + 73 ++hobby 0/5 11 45 ++

Table 8. Evolution of forest raptor populations. Data refer to (1) UTM 10 x 10 km squares with con-firmed/probable nesting sites out of the 35 squares covering Biscay at the beginning of the 1980s (Álvarez et al., 1985), (2) number of breeding pairs located or trends of some species at the beginning of the 1990s (Zuberogoitia & Torres, 1997; Viñuela et al., 1999) and (3) number of known breeding pairs in the first decade of the XXI century (this study). The trends of the species according to the results are shown in the last column.

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data from the 1980s and more recent data from 2009 could well be due to differences in the methods used and the sampling effort.

The honey buzzard follows the same pattern as the two previous species. In the 1980s it was considered very

1999, 2000; Fiuczynski, 2007; Lipták, 2007). It is clear

therefore that in multiple censuses carried out with no

clear objectives, hobbies will be one of the most dif-

ficult species to detect and most territories will be over-

looked. Therefore, population differences between the

Typical pine forest plantations in Biscay. Iñigo Zuberogoitia.

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upwards. However, their nests are extremely difficult to detect. The mingling of non-breeding and breeding individuals makes it even more difficult to detect nests, to which must be added the very large home ranges that breeders use. Despite this we have managed to localise 39 nesting territories in recent years.

Abundant, easy to detect species

The common buzzard is the most common diurnal forest raptor, although we do not know for certain how its population has responded during recent decades. In a study carried out in the Txori Herri valley almost no change was observed in its nesting territories in ten years of intensive monitoring (Zuberogoitia et al., 2006). Curiously, the scenario chosen to carry out our first monitoring project in 1996 showed the highest density of common buzzards in Biscay (mean of 0.45 territories/km2 in an area of 40 km2, see Table 7).

One of the principal problems observed when quan-tifying the breeding population of the species was the effect of a floating population on possible overesti-mates. In the ten years of monitoring we captured 32 adult individuals, of which eight were recaptured at least once and three of them at least three times. There were hardly any changes in the breeding population, any losses/deaths being immediately covered by other adults. Of the 32 individuals captured, 30 were older than four calendar years old and two were three calen-dar years old. Due to 47 controls of 368 ringed com-mon buzzards in the last 17 years, we learnt that the young born in a given territory moved within a radius of 4.35 ± 10.4 km (range = 0 – 40.3) within a control period of de 74.6 ± 77.4 days (range = 37 - 2929). It is clear then that when censuses do not identify the nesting sites, widely varying figures may be obtained because of the presence of a large number of floating individuals, which, moreover, are usually to be found along road verges and on the edges of towns, where they hunt almost all the year and where they are more conspicuous than the individuals who are mainly ac-tive in woodland.

Scarce, difficult to detect species

The goshawk is a clear example of a scarce species that is difficult to detect in a forested landscape such as that of Biscay (see Reich et al., 2004). Censuses carried out in the 1980s defined the species as very scarce and relegated to the largest, most isolated woodlands of the Basque Country (Álvarez et al., 1985). However,

scarce (Table 8), although Galarza (1989) mentioned

the possible existence of some nesting territories in the

Urdaibai Biosphere Reserve. During the pre-breeding

season individuals are frequently seen flying over

woods and attracting attention with their wings open

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as our fieldwork developed, we gradually found new territories to reach the fifteen that we know today, most of which have remained stable throughout a number of years.

The short-toed eagle is another species that is difficult to monitor, since, while birds hunting/flying in mountain meadows of the sierras are easily spotted, most will be from territories located dozens of kilometres away. The few nesting territories that exist in Biscay are hidden in the extensive and impenetrable holm-oak woods of Urdaibai and Truzios and one pair in the beechwoods of Ordunte (Fig. 7). In the 1990s we located a territory in the Txori Herri valley (30T WN09) in a mixed stand of Pinus radiata and oaks. In 1998 the adult male was shot and the territory disappeared. In the mid-1990s another three territories were identified (Table 8), but these, too, were lost.

The red kite (Milvus milvus) is not a typical case, since, although obvious and easily detected, the presence of a wintering population and haphazard movements of individuals at breeding give rise to confusion when attempting to assess its reproductive status. In the first national census of the species in 1994, the presence of two breeding pairs in Biscay was mentioned and between 15 and 20 wintering birds (Viñuela et al., 1999). Ten years later, in the second national census, no breeding pair was detected, while the wintering population was estimated at 50-60 (Cardiel, 2006). However, the census of wintering birds failed to take into account the concentration of red kites in two resting sites (the urban solid waste dump at Lemona and the Karpin Ecological Park in Karrantza), which between them contain about 100 individuals. The noticeable increase in wintering birds of this species in Biscay does not seem to have affected the number of new breeding pairs. However, in 2008 a pair built a nest in a pine tree near the wintering resting site of Karrantza but, although eggs were laid, the outcome was unsuccessful (Eneko Díaz, personal communica-tion).

Scarce, easy to detect species showing a clearly positive trend

In 1995 the first breeding success of booted eagle in Biscay was recorded (Zuberogoitia & Torres, 1997). Since then, the number of pairs has been gradually in-creasing to reach the nine territories confirmed in 2009 (see Table 5). In parallel to these new nesting territories, individuals of the species have been increasingly spot-ted throughout Biscay. However, the number of birds foraging should not be confused with the number of nesting territories since radio-tracking studies have demonstrated that breeding adult birds may fly more than 60 km from the nest to obtain food (see Díaz, 2005; Martínez et al., 2007).

This is not the only case for which an increase has been confirmed for the species. For example, Bosch (2011) documented the appearance of the species in Catalonia, followed by a substantial increase in few years, while Díaz (2005) mentions growing numbers in Navarra, Gipuzkoa, Extremadura, Murcia and Doñana.

The black kite was considered scarce in Biscay in the 1980s and 90s (Álvarez et al., 1985; Gainzarian et al., 1998), although it was seen to be slowly extending its presence in the 1990s without reaching great densities

Iñigo Zuberogoitia coming down from a honey buzzard nest in a larch plantation, after ringing the fledglings. Lander As-torkia.

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(Zuberogoitia & Torres, 1997). However, in the last

decade a notable increase has been observed in its

population and in 2009 we could confirm 70 nesting

territories (see Table 5, Fig. 7). The tendency observed in

Biscay seems to reflect observations made in the rest of

the Iberian Peninsula, where populations of black kite

are clearly on the increase, although not at the same

rate in all regions (Palomino, 2006). Besides the breed-

ing population during the summer several hundreds of

black kites can be observed in the urban solid waste

dumps of Bilbao, Igorre and Lemoiz. These groups are

mainly formed by two and three calendar year old non-

breeding individuals.

Nesting habitat selection and implications for timber management

Most forest raptor nests located in Biscay (85.2% of the 162 platforms found) are found in exotic trees used in forest plantations, mainly Pinus radiata (78.5%), while only 14.8% are found in local deciduous trees (oaks and beeches). All the species monitored site their nests three quarters of the way up the tree, except hobbies, which use carrion crow nests situated in the crowns. However, all use mature trees with sufficiently strong branches to support the nesting platforms (see Table 9). The mean height at which the nests are built in Biscay was 16 m, except in the case of hobbies (27 m). This implies the presence of large trees of considerable

Table 9. Species of tree chosen for nesting by forest raptors in Biscay. Only those nests monitored are shown.

honey buzzard

hobby GoshawkBooted eagle

Sparrowhawk Black kiteCommon buzzard

Pines

Pinus radiata 7 17 8 3 39 6 44

Pinus pinaster 2 1 1

Pinus nigra 1

LarchLarix kaempferi

3 1

EucalyptusEucaliptus globulus

4 1

Holm oakQuercus ilex rotundifolia

2 1 6

OakQuercus robur

1 1 5 1

BeechFagus sylvatica

1 2 1 3

Table 10. Mean values and standard deviation of nest height in tree, trunk diameter at chest height (DBH) and mean distance be-tween trees near the nesting tree; nest size (diameter and thickness) of all the species considered. A total of 162 nests were closely monitored.

honey buzzard

hobby Goshawk Booted eagle Sparrowhawk Black kiteCommon buzzard

Nest height (m) 15.2 ± 4.9 27.3 ± 4.9 16.2 ± 5.9 15.3 ± 5.9 17.5 ± 4.6 17.7 ± 3.6 14.6 ± 4.7

DBh (cm) 40.4 ± 14.3 44.6 ± 11.3 48.3 ± 6.6 50.5 ± 10.5 37.7 ± 9.3 40.4 ± 13.8 43.0 ± 11.1

Tree spacing (m) 5.8 ± 1.9 5.2 ± 1.2 5.4 ± 0.5 4.7 ± 1.3 4.6 ± 1.2 5.3 ± 0.5 5.0 ± 1.6

Size of nest platform

Diameter (cm) 75.2 ± 23.9 47.1 ± 7.9 93.0 ± 7.4 72.5 ± 14.8 57.7 ± 11.8 67 ± 15.1 79 ± 14.2

Thickness (cm) 30.7 ± 3.2 24.9 ± 7.9 48.0 ± 15.3 27.5 ± 6.4 24.5 ± 10.3 39.8 ± 13.9 34.8 ± 18.1

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diameter (see Table 10). However, when timber spe-cies reach this size, they are normally ready for felling, which brings economic interests into conflict with the preferences of the raptors. In the case of eucalyptus, this species is normally cut when it reaches 12-15 years, so that they never reach the diameters that may interest raptors, except in the case of small abandoned stands that have matured and reached a substantial size. The degree of maturity of the nesting habitat selected by raptors is also measured in terms of mean separation between trees, about 5 m, which implies substantial spacing. Curiously, some species, such as honey buzzard, may nest in denser woods of pine, eucalyptus, oak, larch or beech (Table 11), but always in tall trees in the centre of the forest, for example in pines that have escaped past felling programmes in the middle of young eucalyptus.

In total, we have located, ringed and monitored chicks from 289 nests of seven species of diurnal forest raptors (Table 12). Mean productivity was low in most species, mainly due to the high percentage of failed clutches, which exceeded 40% in four of the species and reached 60% in booted eagle. Forestry-related activities (clear-cuts, forest paths, felling, etc.) were responsible for 29% of these failures, a percentage related, as mentioned above, with the conflict of interests between humans and raptor preference for mature trees.

Adverse meteorological conditions, in turn, represented 26.9% of known losses. The strong and persistent spring and summer rains of 2008 and 2009 led to the loss of many nets, especially of hobbies, sparrowhawks, goshawks and booted eagles, while a hail storm in the middle of summer in 2006 destroyed many of the hobby nests being monitored.

Female honey buzzard with her fledgling in the nest. Iñigo Zuberogoitia.

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Changes today will condition the populations of tomorrow. Conclusions

The XX century was marked by the planting of Pinus radiata, especially from the 1950s onwards. The activ-ity peaked in the following decades, when there was a great increase in timber plantations to the detriment of oak woods and grassfields (Michel, 2006). The result-ing changes must have drastically disturbed the forest raptors population, which had to put up with this un-precedented increase in pine forests. Furthermore, most raptors were at that time considered nothing better than vermin and fair game for hunting. It is not surprising, them, that the forest raptor population differed substan-tially from that which exists at the moment.

As we have seen, the presence and density of forest raptors are strongly influenced by forest management practices. For example, hobbies reach their maximum population levels in areas with a high degree of frag-mentation, where open countryside abounds since this

provides the ideal habitat for the species they depend on for their food (see Chapman, 1999; Palacín, 2005). Sparrowhawks reach maximal levels in wooded areas, but also with a high degree of fragmentation, while shunning large expanses of wood land. In contrast, the honey buzzard tends to select just such forests, regard-less of the trees that compose them. In other words, the evolution of forest raptor populations is strongly dependent on changes in the countryside, which will either favour or hinder given species. Some changes are due to natural processes, such as unprovoked fires, floods, storms or disease. Some such events are isolated incidents - for example, the winds of up to 165 kph that destroyed whole swathes of pine woods in Biscay on the 24th of January 2009 - while others may be considered chronic, such as the appearance of the fungus Fusarium circinatum in 1995 which had an effect on some Pinus radiata plantations. Other changes, on the other hand, are obviously the result of human intervention. The lack of continuity in shep-

Table 11. Main type of woodland chosen by forest raptors for nesting in Biscay (1997-2009).

honey buzzard

hobby GoshawkBooted eagle

Sparrowhawk Black kiteCommon buzzard

Pine P. radiata 3 15 8 2 37 4 32

P. pinaster 1 1 1P. nigra 1

Larch 3 1Eucalyptus 3 3 5Pine (P. radiata) x eucalyptus 2 3 1 4Pine (P. radiata) x oak 1 1 2 3Hola oak 2 1Oak 1 1 7 1Beech 1 2 1 4Rock faces 4 2

Table 12. Mean productivity (large chicks/active nest) and reproductive success (large chicks/successful nests) of seven forest raptors in Biscay (1997-2009).

Productivity Reproductive success Failure rate

Mean ± SD n Mean ± SD Range n %

hobby 1.30 ± 1.15 43 2.07 ± 0.68 1-3 23 46.51Sparrowhawk 1.57 ± 1.71 61 2.82 ± 1.29 1-6 34 44.26Goshawk 1.29 ± 1.37 24 2.21 ± 1.05 1-4 14 41.67Booted eagle 0.36 ± 0.50 11 1.00 ± 0 1 4 63.64honney buzzard 1.00 ± 0.93 29 1.61 ± 0.619 1-3 17 41.38Common buzzard 1.32 ± 0.87 104 1.65 ± 0.63 1-3 83 20.19Black kite 2.00 ± 1.12 17 2.43 ± 0.65 1-3 14 17.65

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herding has led to the abandonment of pastures and harvested croplands both in the open countryside and mountain regions (Alberdi, 2001), and later the land has been replaced by commercial forests. Similarly, the patchwork of croplands, pastures and smallhold-ings, surrounded by hedgerows and small pine woods, has tended to disappear in favour of the construction of housing and industrial estates. Not to be forgotten are the economic interests involved in large forests and accompanying market-orientated changes. For example, given the falling prices of pine, this species is gradually being replaced by others. Until recently, eucalyptus was restricted to coastal regions where it was favoured by the milder oceanic weather conditions and it did not grow well in the interior of Biscay due to its inability to withstand frosts and snow. However, the species used until now (Eucaliptus globulus and Eu-caliptus camaldulensis) have now been supplemented with other, more resistant species such as Eucaliptus nitens, meaning that almost all of Biscay is now suited to their cultivation.

Each region offers a pseudo-equilibrium to raptor populations as regards the availability of food, nesting sites and suitable habitats (see Newton, 1979), apart from other biogeographical factors (see, for example Castro et al., 2008; Carrascal & Seoane, 2009; Moleón et al., 2009). In Biscay, for example, there are no large territories of eagles that might represent depredation-competition pressure for space (see Martínez et al., 2008) and eagle owls (Bubo bubo) are scarce, with very few territories spread over the area (Martínez & Zuberogoitia, 2003; Zuberogoitia et al., 2003b). In

this context, such pressure is only exercised by two species - the peregrine falcon (Falco peregrinus) and goshawk. In Great Britain, attempts to recover the goshawk population after its near extinction involved active programmes to reinforce the population (Ken-ward, 2006). The goshawks quickly recovered, but at the same time the number of sparrowhawks, kestrels (Falco tinnunculus), short-eared owls (Asio flammeus) and other similar species declined (Newton, 1986; Petty et al., 2003; Kenward, 2006). For these reasons, it must be borne in mind that any attempt at mountain, woodland or countryside management may have great repercussions on animal species in general and on the forest raptor population in particular.

Throughout this book, we have seen evidence of simi-lar situations in other regions of Europe. Through the application of suitable methods, it should be possible to carry out management à la carte of given species. However, the limitations of each particular region must be taken into account and it should be realised that the benefits provided to one species may harm others. Once we have the basic information necessary, we should monitor the progress of target populations and use management tools that promote their wellbeing, while doing our best to avoid harming others.

Acknowledgements

We are grateful to all those who helped in one way or another in the fieldwork, but especially Lander Astorkia, Fernando Ruiz Moneo, Julen Zuberogoitia, Javier Elor-riaga and Carlos González de Buitrago.